Managing aquatic vegetation on the Rideau Canal

Rideau Canal National Historic Site

About aquatic vegetation

Aquatic plants are a natural part of the Rideau's ecosystem. There are many types of plants including tape grass, coontail, bulrushes, milfoil, pondweed, bladderwort, frogbit, duckweed, and water lily. Many are native to the waters of the Rideau but some, such as Eurasian Watermilfoil, are invasive plants, introduced several decades ago to the Rideau Canal.

Many species of animals such as fish (ie. bass and pike), birds (i.e. loons, herons, blackbirds, ducks, marsh wrens, least bitterns), frogs, turtles and muskrats need these plants to survive. Some of these are “species at risk” (i.e. least bitterns and stink pot turtles).

These plants play an important role in maintaining and improving water quality by stabilizing sediments and absorbing many harmful pollutants.

Excessive aquatic plant growth is due to a number of factors both natural and human induced. These include:

  • Nutrient run-off, primarily phosphorus, into Rideau Canal waters.
  • Cutting but not removing vegetation from the water (i.e. shoreline cutting, boat propellers). This spreads aquatic vegetation since cuttings will actually re-root.
  • Introduction of zebra mussels.

An example of a relatively recent ecosystem change is the introduction of zebra mussels to the Rideau Canal. These mussels have increased water clarity and filtered out small algae, allowing a filamentous green alga (Spirogyra), which zebra mussels cannot filter, to explode in number, creating large “green blobs” in the water. The increase in water clarity due to zebra mussels has also allowed aquatic plants to appear in deeper water.

Aquatic vegetation on the Rideau Canal

What is this vegetation?

Aquatic plants in the waters of the Rideau Canal are an important part of a natural aquatic ecosystem, especially in the ecology of shoreline areas. They provide habitat for fish to spawn, feed and hide from predators. Aquatic plants also play a key role in maintaining and improving the water quality of the Rideau Canal.

Excessive plant growth can interfere with boating, swimming and other recreational water activities, and at times, some control may be necessary.

What can I do?

A significant contributor to excessive aquatic plant growth is the addition of nutrients to waters of the Rideau Canal through activities such as fertilizing and the 'hardening' of shorelines. Landowners within the Rideau Canal watersheds can play a significant role in reducing excessive aquatic plant growth by controlling these activities.

Removing vegetation

If you wish to remove aquatic plants from your property you will require a permit from Parks Canada.

The role of Parks Canada

Parks Canada has been cutting and removing excessive aquatic vegetation from the navigation channel for many years.

It owns mechanical harvesting equipment and operates a program of aquatic plant removal at 20 different locations on the Rideau Canal. The River Styx and downtown Ottawa are the two main problem areas on the Rideau Canal.

Parks Canada continues to contribute to aquatic plant research and monitoring along the Rideau Canal. Scientific knowledge of plant growth trends is a great help in developing more efficient vegetation management programs.

Parks Canada advises waterfront residents on best practices that will help to manage aquatic plant growth.

Parks Canada issues permits for aquatic plant removal. A permit is required prior to any removal of aquatic vegetation.

What you can do

Everyone living within the Rideau Canal watersheds can play a large role in controlling the growth of aquatic plants. The run-off of nutrients into Rideau waters is the single greatest contributing factor to excessive plant growth.

How you can help to control this:

  • Leave (or replant) a minimum three metre buffer of natural vegetation along the shoreline to absorb nutrients before they hit the water.
  • Do not use garden chemicals.
  • Implementing a rural best management program to reduce nutrient/bacteria runoff from agricultural lands.
  • Maintain your septic system in good running order (regular pump-outs and maintain the leaching bed/system).
  • Do not “harden” (i.e. pavement, gravel) any near shoreline areas. This increases direct runoff which degrades water quality.
  • Encourage the upgrade of municipal sewage systems and stormwater retention.

If you wish to remove aquatic vegetation from the Rideau Canal, you will require a permit from Parks Canada.

Please note that the use of chemicals for aquatic plant control is STRICTLY PROHIBITED .

The permit process

Should a waterfront owner wish to remove aquatic vegetation from in front of their property, a permit from Parks Canada is required. This permit is valid for five (5) year and may be obtained by contacting the Rideau Canal Office of Parks Canada.

Listed below are some conditions of the permit:

  • The contractor/landowner is to make all reasonable attempts to harvest and remove the cut aquatic vegetation from the water, and place it upland well above the high water mark.
  • In general, no work will be permitted between March 15th and June 30th (fish spawning time).
  • The area that may be harvested is 50% of the water frontage to a maximum of 10m (30 feet) wide.
  • Harvesting may extend to 30m (100 feet) out into the water body measured perpendicularly from the shoreline.
  • All harvesting activity will occur during daylight hours.
  • All harvested material must be collected and placed a minimum of 15m (45 feet) upland from the upper controlled water level.
  • Emergent aquatic vegetation must not be disturbed.
  • Logs and rocks on the bed of the lake must not be disturbed. 

For more information please contact:
Parks Canada - Rideau Canal
34 Beckwith Street South
Smiths Falls, Ontario, Canada
K7A 2A8
Tel: 613-283-5170 x 284
Toll Free: 1-888-773-8888

It's the law

The protection of fish habitat is provided for in the federal Fisheries Act . Violations of this law can result in substantial fines and/or the risk of imprisonment.

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